Drilling apparatus



April 1951 H. H. VANDERZEE 2,547,609

DRILLING APPARATUS Filed June 9, 1945 5 Sheets-Sheet 2 I w k /63 fizz/"www.-

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April 3, 1951 H. H. VANDERZEE .DR/L L REC/PRO CA TING 5 Sheets-Sheet 5 .DR/LL ROTA T/ON MECHANISM VA LVE MECHA N/SM Q //'5 '79 /26 //am ACCUMULA TOR A25 //J5 ma TANK U2 Patented Apr. 3, 1951 DRILLING APPARATUS Harry H. Vanderzee, Racine, Wis., assignor to Joy Manufacturing Company, a corporation of Pennsylvania Application June 9, 1945, Serial No. 598,524

9 Claims. 1

My invention relates to drilling apparatus, andmore particularly to drilling apparatus of the drill reciprocating type.

' By providing for the drilling tool of a hammer type drill, a reciprocating means which operates to move the drilling tool a slightly greater distance in one direction than in the other during each reciprocation thereof, it will be seen that a feeding of the drilling tool will be obtained. Such reciprocating means may comprise in a preferred form of my invention a friction drive which connects a power operated reciprocating device in driving relation with the drilling tool, the drive slipping slightly in one direction to provide the desired feedng of the tool. In actual operation a slipping may take place in the friction drive during reciprocating movements in each direction, the slipping in one direction being slightly greater than that in the, opposite direction. By providing manually operated means which regulates the amount of slipping in one direction, there is obtained a control of the rate of feed.

An object of my invention is to provide an improved drilling apparatus. Another object is to provide a drilling apparatus having improved means for reciprocating the drilling tool. Still another object is to provide improved reciproeating and feeding means for the drilling tool of a drilling apparatus. Yet another object is to provide improved means operating to reciprocate a drilling tool in such a manner as to effect a feeding of the latter. Another object is to provide, in an improved reciprocating means for a drilling tool, an improved friction drive which slips slightly in one direction of each reciprocation so as to provide a feeding of the tool. Still another object is to provide an improved friction drive for reciprocating a drilling tool, the drive being adapted to slip a small amount in one direction and having associated therewith means for varying the amount of slippage in the drive. These and other objects will appear more fully in the course of the following description.

In the accompanying drawings there is shown for purposes of illustration one form Which my invention may assume in practice.

In'these drawings:

Fig. 1 is a side elevational view of a drilling apparatus in which my invention is incorporated.

Fig. 2 is an end elevational view of the drilling apparatus shown in Fig. 1.

Fig. 3 is an enlarged cross-sectional view taken on the plane of the line 3-3 of Fig. 2.

Fig. i is a fragmentary sectional view taken-on the plane of the line 4-4 of Fig. 3.

Fig. 5 .is an enlarged vertical sectional view taken on the plane of the line 5-5 of Fig. 3.

6 is an enlarged vertical sectional view taken on the plane of the line E E of Fig. 2.

Fig. '7 is a horizontal sectional view taken on the plane of the line 1-! of Fig. 6. 7

Figs. 8 and 9 are fragmentary sectional views taken on the plane of Fig. 6 and showing parts in diiferent positions.

Fig. 10 is an enlarged vertical cross-sectional view taken-on the plane of the line Ill-Id of Fig. 1.

Fig. 11 is a schematic diagram showing the hydraulic control system.

In the illustrative embodiment of the invention there is shown a drilling apparatus, generally designated l mounted on a frame 2; whichis sup ported for movement over the ground by front steering wheels 4 and rear driving wheels 5. An engine 5 mounted on the frame operates through a transmission. l to drive a power shaft 8, and a clutch member 3 slidably mounted-on the shaft 8 is movable by a lever Hi to positions for connecting selectively a pulley l2 and a chain sprocket H1 in driven relation with the shaft. A belt l5 operatively engages the pulley l2 and drives a pulley it which is connected through a universal joint ii and a drive shaft [8 in driving relation with the wheels 5. The chain sprocket M is connected through a chain 20 to a shaft 2! which drives an oil pump 22 nd a mud, pump 24. A belt 25 driven by the shaft 8 operates to drive a compressor 26 which supplies air under pressure to a receiver 28.

Mounted on the frame 2 at its rear end is a mast 3e rotatably supporting adjacent its upper and lower ends, as shown in Fig. 2, transversely extending shafts 32 and 33. Fixed to each of the shafts SZ-and- 33 adjacent its ends are chain sprockets 3 and chains '55 extend around the chain sprockets and are connected at their ends, as shown in Fig. 4, to members 36 whichare provided at their outer sides, see Fig. 3, with grooves 31 slidably receiving flange portions-83 of guide members '39 extending longitudinally of the mast at opposite sides of the latter. Extending transversely of the mast between the members 36 is a member it having bores 4! at its opposite ends rotatably receiving inwardly projecting portions 32 on the members 36. Formed in the mid portion of the member it is an opening 63. and a generally cylindrical casing 441 extends through the opening 53 and is provided'at diametrically opposite points with projecting portions 46 having bores 47 which rotatably receive portions 43 projecting inwardly through openings in the sides of the member 48 and formed on plate members 59 attached to the sides of the member 40, as by screws It will be seen that "is member 40 and the casing M. are similar to parts of a universal joint, making it possible for the casing to be moved angularly in any direction.

Extending axially through the casing 44 is a shaft 52 which is rotatably supported by bearings 53 and 54, the bearing 53 being carried by the lower end of the casing and the bearing 54 being carried by a cover plate 55 fixed to thetop of the casing. A ratchet wheel 56- is fixed to the portion of the shaft 52 extending between the bearings 53 and 54, and hub portions 58 formed on the ratchet wheel engage the inner races of the hearings to prevent axial movement of the shaft relative to the casing. Connected to the lower end of the shaft 52 in any suitable manner is a drill rod 59 carrying a drill bit 60 at its lower end. Extending axially through the shaft 52 is a passage 6| which is connected at its upper end by a conduit 52 and a passage 83 in the cover plate 55, in communication with a hose 04 leading to a supply of water under pressure. Water delivered to the passage SI is conducted through suitable passage means in the drill rod and bit to the bottom of the hole for washing away cuttings.

Formed on one side of the casing 44 is a projecting portion 65 having alined bores 05 and 61 containing cylindrical linings 68 in which opposite ends of a piston I are reciprocably received. The adjacent ends of the bores 53 and 07 open into a space 'H communicating with the interior of the casing 44, and a pawl '52 is reciprocably received in a recess I3 in the side of the piston portion extending through the space 'H. A spring I4 acts between the inner end of the recess 13 and the pawl for urging the latter into engagement with ratchet teeth I5 formed on the wheel 56. Acting between one end of the piston I0 and a plate I6 closing the outer end of the bore 66 is a spring '11 which yieldingly urges the piston toward the bore 01. Opening through a cover plate I8 for the outer end of the bore 61 is a conduit 80 which is intermittently connected by means which will shortly be described, in communication with means delivering a liquid under pressure and with a liquid discharge. When liquid is supplied under pressure to the bore 6'5, the piston '50 is moved against the force of the spring i? and the pawl I2 operates to rotate the ratchet wheel 55 through a small 'angle. Rotation of the ratchet wheel causes the shaft 52 and the drill rod 59 to rotate and change the angular position of the drill bit for cutting material.

When liquid is vented from the bore 01, the piston 'IE! is moved by the spring I! and the pawl slides over the teeth I5 to a new position on the ratchet wheel.

Rotatably supported on one end of the shaft 33 at the lower end of the mast, as shown in Fig. 10, is a brake drum 85, and rotatably supported on the opposite end of this shaft is a sprocket wheel 86. Clutch members 8? and 88 are slidably keyed to the shaft 33 and are adapted to be actuated by levers 89 and 9b pivotally supported on the frame 2 for controlling, respectively, the connection of the brake drum and the ratchet wheel 86 to the shaft.

Surrounding the brake drum 85 is a brake band 92 having fixed to its ends, as shown in Pig. 6, members 93 and 94 providing radially extending flange portions 95 and 96. A bolt 0'1 extends through openings in the flange portions 95 and 96, and a spring 98 acts between the flange portion 90 and a plate 99 abutting a nut I59 on the bolt for yieldingly holding the brake band in engagement with the drum. Pivotally connected to the member 93 and to a piston rod IOI, is a rod I02. The piston rod IelI extends axially through a bore I03 formed in a cylinder block 504 supported by brackets I05 on the frame 2. Slidably contained within the bore I03 is a piston I0 which is fixed to the rod IEIE, and passages I08 and I00 open into opposite ends of the bore I03 for conducting a liquid relative to the latter under the control of a valve mechanism, generally designated H0, so as to effect a reciprocation of the piston I01.

The valve mechanism H0 comprises a valve receiving bore H2 formed in the cylinder block I04 with its axis parallel to theiaxis of the bore I03, and a valve member H4 slidable longitudinally in the borev H2 and engageable at its ends with flange portions H5 formed on annular members IIG fixed, as by screws In, to the cylinder block at opposite ends of the bore H2. Surrounding the mid-portion of the bore H2 is an annular groove H8 opening into a chamber H9 of an accumulator to which a liquid such as oil is delivered by a conduit I20. Spaced longitudinally of the bore H2 at opposite sides of the groove H8 are annular grooves I2I and E22 communicating respectively with the passages I58 and I00, and spaced outwardly from the grooves i2! and I22 are grooves I23 and I24 communicating, as shown in Fig. '7, with exhaust conduits I25 and I25. The valve member H4 is provided with an axial bore I28, and a rod I is slidable in the bore I28 and is connected by an arm I3I to the rod I02 for actuation by the latter. The end portions of the rod I30 are slightly reduced in cross section so as to provide shoulders which are engageable by annular members I33 and I34. The distance between the shoulders is somewhat greater than the length of the valve member H4, and the annular members I33 and I34 are yieldingly held against the shoulders by springs I35 and E36, the spring I35 acting between the arm IBI and the member I33, and the spring 230 acting between the annular member I34 and another annular member I31 abutting a nut I558 threaded on the end of the rod. Formed in the valve member I I4 are longitudinally spaced annular grooves I40, IM and I42, the groove I operating as a supply groove and the grooves IM and I42 operating as'exhaust grooves. When the valve member engages the flange portion H5 on the annular member H6 at the right-hand end of the valve bore, as shown in Fig. 6, the groove I40 connects the groove H8 in communication with the groove I22 and the groove I4I connects the groove I2? in communication with the groove I23. In the opposite limiting'position of the valve 5 member the groove I40 connects the groove H8 with the groove I2I, and the groove I42 connects the grooves I22 and I24.

Formed in the lower portion of the chamber H0, as Shown in Fig. 6, are stepped coaxial bores I45 and I47, and a piston I48 is provided with stepped portions I49 and I50 which are reciprocable in the bores I46 and I41, respectively. A cap I M covers the lower end of the bore I41, and a conduit I52 extends through an opening in the cap and connects the space beneath the piston I48 .in communication with the air receiver 28. It will be seen that the air pressure acting on the piston I68 urges the latter upwardly against the action of the liquid in the chamber II9. If the pressure on the liquid in the chamber II9 becomes enough greater than the air pressure in the receiver 26, the piston I 48 is forced downwardly and, as it approaches its lower position, the piston portion I66 uncovers a port I56 opening into the bore I66 and communicating with an exhaust conduit I55. Liquid then escapes through the conduit I55 until the pressure on the liquid is reduced to a point at which the piston I46 is again raised by air pressure and overruns port I54;

Referring to Fig. 5, it will be noted that the conduit 66 for conducting fluid relative to the piston ID of the drill rotating mechanism opens into one end of a bore I66 formed in the projecting portion 65 of the casing 46. The other end of the bore I66 opens into an enlarged bore "SI, and a valve member I62 is reciprocable in the bore I66 and has a head portion I63, engageable with the shoulder between the bores. Extending axially through the valve member I62 is a passage I66, and formed in the periphery of the portion of the valve member fitting the bore I66 are longitudinal grooves I65. When the valve member has its head portion I63 engaging the shoulder between the bores, the passage IBt provides the only communication between the bores, and the flow of fluid through this passage is somewhat restricted. When the head portion I63 is moved away from the shoulder, the bores I66 and. I6I communicate with each other through the grooves I65 as well as the passage I64. Closing the bore I6! is a cover plate I66, and a conduit I66 communicates with the bore I6I through a port in this cover plate and leads, as shown in Fig. '7, to the groove I22 surroundingthe valve bore II2. Formed on the cover plate are projecting abutment portions I16 which prevent the valve member from moving into engagement with the cover plate so as to out 01f communication between the bore I6I and the conduit I68.

When the groove I22 is connected to the supply groove II8 by the valve H6, oil flows through the conduit I66 to the bore I6I where it acts on the valve member I62 and forces the latter to a position with its head engaging the shoulder between the bores. The oil is then conducted through the passage I64 and the conduit 86 to the piston 16 for I'llOVlIlg the latter against the spring 17. When the groove I22 is connected to the exhaust groove I 24, the oil escapes from the piston "I6 through the conduit 86 and acts on the valve member I62 to move it into engagement with the abutment portions E76. The passage I64 as well as the grooves I65 in the valve I62 conduct the oil from the conduit 66 to the bore I6I and the conduit I68.

7 The sprocket wheel 86 on the shaft 33 is adapted to be driven by a hydraulic motor I I2 through a chain I73. It will be seen that a raising of the drilling tool may be obtained by operating the clutch lever 66 to connect the sprocket wheel 86 to the shaft 33 through the clutch member 88, and then operating the motor I I2, after the clutch member 6'! is actuated to disconnect the brake drum 65 from the shaft 33.

The hydraulic system includes, as shown in Fig. 9, the oil pump 22 taking oil from a tank I15 through a conduit I16 and discharging it through a conduit IT! to a valve box I16 containing two manually operated valve devices, one controlling the flow of oil through the conduit I26 to the chamber I IQ of the accumulator and the other controlling the flow of oil through a conduit I86 to the hydraulic motor I'IZ. Excess oil supplied to the chamber H9 is returned to the valve box through the conduit I55 and oil supplied to the motor I12 is returned to the valve .box through a conduit I 6| the return side of the valve box being connected to the tank I'I5 through a con-. duit I83.

The operation of the mechanism described is as follows: Assuming that the drilling apparatus has been moved to a position for drilling, the

1 clucht lever I6 is actuated to connect the pump 22 in driven relation with the power shaft 8, and, at the same time, the compressor 26 is driven by the power shaft to deliver air under pressure to the receiver 26. The clutch lever 89 is actuated to connect the bake drum 85 to the shaft 33, and the clutch member 68 is positioned to disconnect the sprocket wheel 86. from the shaft 63. The valve device in the valve box controlling the flow of oil to the accumulator is opened so that oil passes through'conduit I26 to the chamber II 9. If the valve H4 is in the position shown in 6, the oil passes from the til chamber H6 through the groove I I8, the valve groove M6, the groove i232 and the passage I69 to the bore I66 at the right-hand end of the piston 61. The opposite end of the bore I 63 is connected at this time through passage I66, groove I2I, valve groove i6! and groove I23 to the discharge conduit I25 which leads to the tank I75. The oil actin on the right-hand end of piston I6? moves the latter to the left forcing oil out of the bore I63 at the opposite end of the piston, and the rods EEH, I62 and I36 move to the left with the piston. The connection of the rod I62 to the brake band 62 is such that it acts with the spring 66 .in pulling the band about the drum 85 when traveling to the left. The drum Will then be rotated in a counter-clockwise direction with minimum slippage betweenthe drum and the brake band, and the chains 35 will be actuated to force the drill rod downwardly. As the rod I66 moves to the left the annular member I36 engages the valve member H6 and moves it into engagement with the flange portion H5 on the annular member II 6 at the left-hand end of the bore II2. Any further movement of the rod I36 to the left merely results in a compression of the spring I36. .While the valve member II 6 is at the right-hand end of the bore II2, oil passes from the groove I22 to the'conduit I66 which conducts it, as shown in Fig. 5, to the bore 56! where it acts on the valve member I62 and forces the latter to the left with its head portion l63engaging the shoulder between the bores I66, NH. The oil then passes through the passage I66 and the conduit 86 to the piston 16 for moving the latter against the action of the spring I1 and eifecting a'rotation of the ratchet wheel 56. The flow of oil through the passage I64 is restricted so as to prevent movement of the piston T6 at such a rate as to cause the ratchet wheel to spin.

When the valve member H6 reaches the lefthand end of the bore H2, oil is supplied from the chamber H6 through the groove IIS, the valve groove M6, the groove i2I and the passage I66 to the left-hand end of the bore I63. At the same time oil is vented from the righthand end of the bore I 66 through passage I39, groove I22, valve groove I62, groove i2 5 and con- *7 duit M6 to the tank F55. Oil is also vented from the piston ls through conduits 3% H58, grooves I22, valve groove M2, groove 12 i and conduit 25 to the tank. The flowof oil from conduit 89 through here I66 causes the valve membe l82 to move into engagement with the abutment portions 510 so that the escape of oil may take place through the valve grooves I65 as well as the passage E64, the rate of escape being suflicient to permit rapid movement of the piston i!) by the spring 11. Movement of the piston Iii by the spring l'l results in a sliding of the pawl 72 over the ratchet teeth E5 to engage the ratchet wheel at a different point. Oil suppiied to the left-hand end of the bore Hi3 operates to move the piston ill? and the rods Hi2 and 135! to the right, the rod Hi2 pulling on the brake band in such a manner as to release it slightly from the drum and cause a slight slipping of the band on the drum. As the rod I moves to the right, the annular member l33 engages the valve member lid and moves it to the right-hand end of the bore H2, connecting the left-hand end of the bore to discharge and the right-hand end to oil supply. It will be seen that by reason of the slipping of the brake band on the drum, the rotation of the drum in a clockwise direction will be slightly less than in a counterclockwise direction, the difference in rotation determining the amount of feeding of the drilling tool. By adjusting the nut iilii on the rod 9?, the amount of slippage may be regulated so as to give any desired rate of feed. To raise the drilling tool out of the hole, the clutch member Bl is actuated to disconnect the brake drum from the shaft c3 and the clutch member 83 is moved to connect the sprocket wheel 86 to the shaft. The valve device in the valve box H9 controlling the supply of oil to the motor i'5'2 is then actuated to supply oil to the latter for driving the sprocket wheel 86 in a direction to raise the drill rod. The accumulator play the important function of reducing shocks and of, while there is being used a relatively efiicient force transmitting hydraulic fluid, providing a velocity of impact much greater than would be possible with fluid transmitted without the accumulator from the pump through ail of the necessary passages.

As a result of my invention there is provided an improved drilling apparatus of the drill reciprocating type. The drill operating mechanism produces a reciprocating action for efiecting a cutting of material, and the reciprocating action is such that a feeding of the drilling tool is obtained.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration, and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a drilling apparatus, a feeding and actuating mechanism for a drilling implement including means for supporting a drilling implement, means guiding said supporting means for movement in a direction longitudinal of the drilling implement, and means for reciprocating said supporting means on said guiding means including rotary guides rotatably supported by said guiding means at opposite ends of the latter, a flexible element circulating about said rotary guides and operatively connected to said supporting means, a friction drum operativel-y connect.- ed to one of said rotary guides for driving the same to eifect circulation of said flexible element, a friction band operatively engaging said drum, and power operated means connected to said fric- .tion band for oscillating the latter and operating to effect a slipping between said band and said drum durin the reversal at one end of each oscillation.

'2. In a drilling apparatus, a feeding and actuating mechanism for a drilling implement including means rotatably supporting a drilling implement, means guiding said supporting means for movement in a direction longitudinal of the drilling implement, fluid actuated means carried by said supporting means for effecting a stepped rotation of said drilling implement, means for reciprocating said supporting means on said guiding means including a friction drum operatively connected with said supporting means and upon oscillation reciprocating the latter, a friction band operatively engaging said drum, means yieldingly engaging opposite ends of said friction band for holding the latter in yielding engagement with said drum, 2. piston reciprocable in a cylinder bore and connected to one end of said friction band, means alternately connecting the opposite ends of said piston to a fluid supply and to exhaust, and means connecting said fluid actuated means in communication with the space at one end of said piston 3. In a drilling apparatus, a feeding and actuating mechanism for a drilling implement including means for supporting a drilling implement, means guiding said supporting means for movement in a direction longitudinal of the drilling implement, and means for reciprocating said supporting means on said guiding means including rotary guides rotatably supported by said guiding means at opposite ends of the latter, a flexible element circulating about said rotary guides and operatively connected to said supporting means, a friction drum operatively connected to one of said rotary guides for driving the same to effect circulation of said flexible element, a split friction band operatively engaging said drum, power operated means connected to one end of said friction band for oscillating the latter, and means coacting with the other end of said friction band for yieldingly biasing it towards said first mentioned end.

4. In a drilling apparatus, in combination, a reciprocatory drilling implement, and an actuating mechanism for imparting a rapid reciprocation to the drilling implement to effect the drilling of a hole with a percussive action includin a hydraulically operated motor of the reciprocating type, means for operatively connecting said motor to said drilling implement, a liquid. pump, a conduit for delivering liquid from sa d pump to said motor, a chamber to which said conduit delivers liquid and from which liquid is delivered to said motor, said chamber having a movable Wall associated therewith, and means for causing said movable Wall to exert, irrespective of the position of said wall relative to said chamber, a substantially uniform pressure upon the liquid Within said chamber including means providing a surface subjected to a substantially constant gaseous pressure acting in a direction to reduce the efiective volume of said chamber.

5. In a drilling apparatus, in combination, a reciprocatory drilling implement, and an actuating mechanism for imparting a rapid reciprocation to the drilling implement to effect the drilling of a hole with a percussive action including a hydraulically operated motor of the reciprocating type, means for operatively connecting said motor to said drilling implement, a liquid pump, a conduit for delivering liquid from said pump to said motor, a chamber to which said conduit delivers liquid and from which liquid is delivered to said motor, said chamber having a movable wall associated therewith, means for causing said movable wall to exert, irrespective of the position of said Wall relative to said chamber, a substantially uniform pressure upon the liquid within said chamber including means providing a surface subjected to a substantially constant gaseous pressure acting in a direction to reduce the effective volume of said chamber, and means governed by the position of said movable wall for venting liquid from said chamber.

6. In a drilling apparatus, the combinat on comprising a reciprocatory percussive drilling implement, and mechanism for reciprocating said implement to effect drilling with a percussive action and for feeding said implement toward the work as the hole deepens during driling comprising a frictional slip driving device including a friction band and drum drive, reciprocating means for actuating said friction band to cause oscillatory motion of said drum, said band slipping a slight amount at the end of the working stroke of the implement. when the latter is sufficiently resisted by the work, and a slightly greater amount upon the other stroke, to cause drum oscilation through a distance greater in the latter direction than in the former, means for transforming the oscillatory motion of said drum to a reciprocatory motion, and means for transmitting said reciprocatory motion to said drilling implement.

7. In a drilling apparatus, the combination comprising a reciprocatory percussive drilling implement, and mechanism for reciprocating said drilling implement to effect drilling with a percussive action and for feeding said drilling implement toward the work during its reciprocation and as the hole deepens comprising a frictional drive device including an oscillatory friction drum, a friction band operatively engaging said friction drum, power operated means for oscillating said friction band and including means operating to effect different frictional engagements between said band and said drum during the opposite movements of each oscillation, means for transforming the oscillatory motion of said drum to a reciprocatory motion, and means for transmitting such reciprocatory motion to said drilling implement.

8. In a drilling apparatus, the combination comprising a reciprocatory percussive drilling implement, and mechanism for reciprocating said implement to effect drilling with a percussive action and for feeding said implement toward the work during reciprocation thereof and as the hole deepens including a frictional driving device and transmission connections between said driving device and said drilling implement, said driving device including an oscillatory friction drum, a friction band surrounding said drum and having ends movable rela tive to each other for varying the frictional engagement between said band and said drum, means for yieldingly urging the ends of said friction band toward each other and adapted to yield to permit slippage of said band when said implement is resisted by the work, and power operated means connected to one end of said band and operating to effect oscillation of the latter.

9. In a drilling apparatus, the combination comprising a reciprocatory percussive drilling implement, and mechanism for reciprocating said drilling implement to effect drilling with a percussive action and for feeding said implement toward the work during reciprocation thereof and as the hole deepens including a fluid operated reciprocatory motor having an automatically actuated fluid distributing valve means, means for transforming the reciprocatory motion of said motor to an oscillatory motion including an oscillatory transmission device, means for transforming said oscillatory motion to a reciprocatory motion, means for transmitting such reciprocatory motion to said drilling implement, and means for rotating said drilling implement during actuation thereof including a fluid operated cylinder and piston mechanism and means controlled by said fluid distributing means for supplying fluid to and venting fluid from said cylinder and piston mechanism.

HARRY H. VANDERZEE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

